1. Field of the Invention
The present invention relates to a method of frequency utilization in mobile communication in the case where mobile communication frequency bandwidths for uplink communications and downlink communications are not arranged symmetrically, and more specifically, to a method of frequency utilization in mobile communication which is effective in the case where uplink communication traffic is larger than downlink communication traffic.
2. Description of the Background Art
Conventionally, in the cellular mobile communication, bandwidths of the identical width have been used for uplink communication frequency bandwidth and downlink communication frequency bandwidth. Also, the conventional cellular mobile communication has been mainly speech communications in which a problem of having unbalanced uplink communication traffic and downlink communication traffic did not occur.
In conjunction with the recent rapid spread of mobile communication there is an increasing demand for newly allocating frequencies to mobile communication. However, the frequencies are getting stringent and it is now becoming difficult to arrange uplink communication frequency bandwidth and downlink communication frequency bandwidth symmetrically in the identical width as in conventional cases. Also, recently, data communications are becoming widespread even in mobile communication, and when actual mobile data communication service forms are considered, they are expected to be mostly of forms of utilization in which an access is made from a mobile terminal to a database connected to a fixed network and data are read out. In such cases, it is expected that downlink communication traffic becomes larger than uplink communication traffic. Consequently, it is practical as well as efficient to make the downlink communication frequency bandwidth wider than the uplink communication frequency bandwidth. However, a method of frequency utilization in the case where widths of the uplink communication frequency bandwidth and the downlink communication frequency bandwidth are different in cellular mobile communication has not been investigated conventionally.
Therefore an object of the present invention is to provide a method of frequency utilization in mobile communication which is capable of realizing efficient frequency utilization in the case where widths of the uplink communication frequency bandwidth and the downlink communication frequency bandwidth are different in cellular mobile communication.
According to one aspect of the present invention there is provided a method of frequency utilization in mobile communication having an uplink communication frequency bandwidth Wu which contains n pieces of carriers within a frequency bandwidth W, a first downlink communication frequency bandwidth Wd1 which contains n pieces of carriers within a frequency bandwidth W similarly, and a second downlink communication frequency bandwidth Wd2 which contains m pieces (m less than n) of carriers within a frequency bandwidth V, the method of frequency utilization in mobile communication characterized by: selecting m pieces of carriers among the n pieces of uplink communication carriers as selected carriers; setting the n pieces of uplink communication carriers of the uplink communication frequency bandwidth Wu and the n pieces of downlink communication carriers of the first downlink communication frequency bandwidth Wd1 respectively in one-to-one correspondence; setting said m pieces of the selected carriers and the m pieces of downlink communication carriers of the second downlink communication frequency bandwidth Wd2 respectively in one-to-one correspondence; carrying out communications using a corresponding carrier in the first downlink communication frequency bandwidth Wd1 and a corresponding carrier in the second downlink communication frequency bandwidth Wd2 as downlink communication carriers in a case of using said selected carrier as an uplink communication carrier; and carrying out communications using only a corresponding carrier in the first downlink communication frequency bandwidth as a downlink communication carrier in a case of using a carrier other than said selected carrier as an uplink communication carrier.
According to another aspect of the present invention there is provided a method of frequency utilization in mobile communication having an uplink communication frequency bandwidth Wu which contains n pieces of carriers within a frequency bandwidth W, a first downlink communication frequency bandwidth Wd1 which contains n pieces of carriers within a frequency bandwidth W similarly, and a second downlink communication frequency bandwidth Wd2 which contains m pieces (m less than n) of carriers within a frequency bandwidth V, the method of frequency utilization in mobile communication characterized by: selecting m pieces of carriers among the n pieces of uplink communication carriers as selected carriers; setting the n pieces of uplink communication carriers of the uplink communication frequency bandwidth Wu and the n pieces of downlink communication carriers of the first downlink communication frequency bandwidth Wd1 respectively in one-to-one correspondence; setting said m pieces of the selected carriers and the m pieces of downlink communication carriers of the second downlink communication frequency bandwidth Wd2 respectively in one-to-one correspondence; carrying out communications using either a corresponding carrier in the first downlink communication frequency bandwidth Wd1 or a corresponding carrier in the second downlink communication frequency bandwidth Wd2 as downlink communication carriers in a case of using said selected carrier as an uplink communication carrier; and carrying out communications using a corresponding carrier in the first downlink communication frequency bandwidth as a downlink communication carrier in a case of using a carrier other than said selected carrier as an uplink communication carrier.
According to another aspect of the present invention there is provided a method of frequency utilization in mobile communication having an uplink communication frequency bandwidth Wu which contains n pieces of carriers within a frequency bandwidth W, a first downlink communication frequency bandwidth Wd1 which contains n pieces of carriers within a frequency bandwidth W similarly, and a second downlink communication frequency bandwidth Wd2 which contains m pieces (m less than n) of carriers within a frequency bandwidth V, the method of frequency utilization in mobile communication characterized by: setting the n pieces of uplink communication carriers of the uplink communication frequency bandwidth Wu and the n pieces of downlink communication carriers of the first downlink communication frequency bandwidth Wd1 respectively in one-to-one correspondence; setting the n pieces of uplink communication carriers of the uplink communication frequency bandwidth Wu and the m pieces of downlink communication carriers of the second downlink communication frequency bandwidth Wd2 respectively in multiple-to-one correspondence; and carrying out communications using both a carrier in the first downlink communication frequency bandwidth Wd1 and a carrier in the second downlink communication frequency bandwidth Wd2 which are corresponding to a carrier used in an uplink, as downlink communication carriers.
According to another aspect of the present invention there is provided a method of frequency utilization in mobile communication having an uplink communication frequency bandwidth Wu which contains n pieces of carriers within a frequency bandwidth W, a first downlink communication frequency bandwidth Wd1 which contains n pieces of carriers within a frequency bandwidth W similarly, and a second downlink communication frequency bandwidth Wd2 which contains m pieces (m less than n) of carriers within a frequency bandwidth V, the method of frequency utilization in mobile communication characterized by: setting the n pieces of uplink communication carriers of the uplink communication frequency bandwidth Wu and the n pieces of downlink communication carriers of the first downlink communication frequency bandwidth Wd1 respectively in one-to-one correspondence; setting the n pieces of uplink communication carriers of the uplink communication frequency bandwidth Wu and the m pieces of downlink communication carriers of the second downlink communication frequency bandwidth Wd2 respectively in multiple-to-one correspondence; and carrying out communications using either a carrier in the first downlink communication frequency bandwidth Wd1 or a carrier in the second downlink communication frequency bandwidth Wd2 which is corresponding to a carrier used in an uplink, as a downlink communication carrier.
According to another aspect of the present invention there is provided a method of frequency utilization in mobile communication having an uplink communication frequency bandwidth Wu which contains n pieces of carriers within a frequency bandwidth W, a first downlink communication frequency bandwidth Wd1 which contains n pieces of carriers within a frequency bandwidth W similarly, and a second downlink communication frequency bandwidth Wd2 which contains m pieces (m less than n) of carriers within a frequency bandwidth V, the method of frequency utilization in mobile communication characterized by: carrying out communications by selecting one or a plurality of carriers to be used in a downlink, independently from a carrier used in an uplink.
Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.